1. Field of the Invention
This invention concerns an excavation device with a rotary cutter having a horizontal axis. To be more exact, the invention concerns an excavation device with a rotary cutter having a horizontal axis, the device comprising additional excavation means suitable to provide an excavation face without any unexcavated spaces.
The device of the invention can work on any kind of ground and is suitable to excavate partitions, pits, trenches, ditches, etc.
2. Discussion of Prior Art
The state of the art covers a plurality of excavation apparatuses comprising rotary excavation tools of which the axis of rotation can be vertical or horizontal.
Among the excavation tools with a horizontal axis the most widely used are cutters, to which we shall refer in the description that follows.
These cutters normally consist of two pairs of wheels having their axes parallel to each other and also parallel to the surface being excavated.
In the most modern types each pair of cutter wheels is generally driven by at least one hydraulic motor which sets the wheels in rotation through suitable transmission means.
The excavation tools of the state of the art, whilst they ensure an excellent performance with regard to their excavation capability, entail great drawbacks concerning the obtaining of a continuous excavation face without any unexcavated spaces. In other words the tools of the state of the art do not ensure efficient excavation conditions in the portions of ground between the cutter wheels belonging to the same pair of cutter wheels nor in the zones between one pair of cutter wheels and the other pair.
The space between the cutter wheels belonging to the same pair of cutter wheels is determined by the dimensional requirements of the bearing structure and by the dimensions of the means supplying energy or transmission of motion.
The space between two neighbouring pairs of cutter wheels is determined by problems linked to the danger of contact between the peripheral tools of one pair of cutter wheels and the other pair.
The state of the art includes some solutions disclosed to overcome the above problems, but the results thereof are unsatisfactory from the points of view of working efficiency and constructional complexity.